1. Technical Field of the Invention
The present invention relates to the RF coverage areas of antennas, and more particularly, to the improvement of RF coverage about antennas with coverage areas partially shielded by an equipment housing.
2. Description of Related Art
The use of microcellular network coverage areas involves the placement of antennas in areas providing limited RF propagation characteristics. The use of microcells permit better coverage over particularly high traffic areas within a cellular network. Presently existing configurations of antennas and base station equipment are connected to each other by coaxial cables. However, this configuration is being replaced by integrated antenna and equipment housing configurations. Combination of the antenna with the equipment housing minimizes installation requirements. However, this solution raises the problem of RF signal blocking caused by the equipment housing being located next to the antenna.
Placement of the antenna in close proximately to the equipment housing creates a shadow in the RF coverage area of the antenna. The shadow is caused by the equipment housing blocking all signals from propagating in the direction of the housing. This degrades or eliminates RF coverage in the direction of the housing. One solution to this problem has been to place the antenna above or below the housing in order to provide omnidirectional coverage. While this approach is physically simple to implement, it is aesthetically offensive and does not work well with indoor applications where the antenna and housing configuration is easily visible.
Another type of indoor application in microcellular networks uses microstrip patch antennas. These types of antennas are completely adequate when placed against a wall but are unsuitable for placement in the center of a room or large open area. The unsuitability arises from the limited coverage area of microstrip patch antennas, which only provide a 90.degree. beamwidth. Thus, there is a need in microcell applications for an antenna and equipment housing configuration enabling omnidirectional RF coverage patterns about the antenna with limited or no blind spots within the coverage.